This invention relates to rotatably adjustable light shields for shielding and suspending portable trouble lamps.
Portable trouble lamps are extensively used to illuminate areas which are difficult to light by stationery light fixtures, such as gasoline engines located under the hoods of automobiles. Such trouble lamps frequently include a lamp shield for concentrating the rays of the lamp along a particular direction, as well as a suspension means, such as a hook, for suspending the lamp in the vicinity of the area to be illuminated.
Ideally, such a light shield should include a suspension means which is rotatably adjustable so that the light beam transmitted through the shield can be easily and conveniently directed toward a desired area. Further, whenever the handle of the trouble lamp is turned to rotatably adjust the beam of light, the user should not have to wait for the lamp to swing back into an equilibrium position before knowing the amount of angular adjustment he has made on the light beam. Rather, the suspension mount should be capable of immediately indicating to the user the exact amount of angular adjustment made on the direction of the light beam at the time the handle of the trouble lamp is turned. Furthermore, the rotatably adjustable suspension mount should have some sort of means for adjusting the amount of torque necessary to adjust the position of the light beam to a desired angle. Moreover, the light shield should serve not only to direct the light emitted from the light bulb of the lamp into a concentrated beam, but should also serve to protect the fragile light bulb disposed therein from all manner of mechanical shocks. Finally, the light shield should be easily and conveniently mountable onto a variety of trouble lamps.
Rotatably adjustable light shields for portable trouble lamps are known in the prior art. Examples of such light shields are disclosed in U.S. Pat. Nos. 2,569,068, 2,602,880, 2,694,776, 2,707,229, 3,808,420, 3,828,181, and 4,019,047.
However, each of these prior art light shields falls short fulfilling at least one of the above mentioned ideal criteria. For example, the rotatably adjustable suspension mount disclosed in U.S. Pat. No. 4,019,047 makes no provision for adjusting the amount of torque which must be applied between the suspension hook and the body of the shield member before angle of the light beam may be changed. Furthermore, there is no provision for providing a signal to the user as to the amount of angular adjustment made when the suspension mounting of this invention is used. Finally, the shield member of this invention does not protect the top of the fragile light bulb disposed therein.
Similarly, the rotatably adjustable trouble light shields disclosed in U.S. Pat. Nos. 3,828,181, 3,808,820, and 2,707,229 also have no provision for adjusting the amount of torque which must be applied between the suspension mount and the body of the shield member before the angle of the light beam may be adjusted. Furthermore, the rotatably adjustable suspension means in U.S. Pat. No. 2,707,229 must be inconveniently depressed toward the body of the light shield member before an angular adjustment may be made. Likewise inconvenient is the suspension arrangement disclosed in U.S. Pat. No. 3,808,420, which must be pulled away from the body of the light shield member before an angular adjustment may be made.
Finally, none of the suspension means for the light shields disclosed in U.S. Pat. Nos. 2,569,068, 2,694,776 or 2,602,880 provides any sort of signal to the user as to the amount of angular adjustment made on the light beam when the handle of the trouble lamp is grasped and turned by the user. Rather, in each of these units, the user must grasp the handled trouble lamp, turn it to place the beam in the desired location, and then release the handle of the lamp and hope that the light beam will still be focused on the desired area after the lamp sways back and forth a couple of times from its suspension mount in seeking a new stable rest position. Additionally, the light shields disclosed in U.S. Pat. Nos. 2,602,880 and 2,694,776 leave the top portion of the delicate electric light bulb exposed to mechanical shock, and thus do not effectively shield the light bulbs within their respective shield assemblies.